1. Field of the Invention
The field of the invention is that of toys incorporating drawing devices. The particular nature of the invention is an automatic device for drawing patterns, based on the movement of two interacting pendulums.
2. Description of Related Technology
Devices intended to produce various designs and including two pendulums mounted to swing relative to each other are known. These instruments produce intricate and fanciful line configurations and designs by employing two pendulums coupled with an inscribing or drawing tool. The motion of each pendulum is superimposed simultaneously upon the tool so that the ultimate movement of the tool is the resultant of the individual pendulum movements. The various structural parts or elements of the instrument are so oriented that the inscribing tool can be caused to trace the design or configuration on a sheet of paper or plastic corresponding to its path of movement. However, due to the periodic but decreasing motion of the pendulums, the basic pattern traced will remain the same but will decrease in magnitude, providing a symmetrical and attractive design. Thus, since the resultant movement of the inscribing instrument is a function of the period or timing of the pendulum swing, an infinite number of patterns may be achieved by adjusting the relative position of the respective pendulum weights, which in turn changes the pendulum period.
For example, U.S. Pat. No. 3,143,807, issued to Christie, discloses a pendulum drawing device which includes a pair of pendulums that are supported with respect to a drawing surface. The upper portions of the pendulum arms are connected to a writing instrument by a pair of wires 4. Tension is created on the wires by a counter weight 6. Weights are located at the lower ends of the pendulum arms. The longitudinal position of the weights may be adjusted to alter the motion of the pendulums. The pendulums are pivoted so as to create a design on a paper sheet.
U.S. Pat. No. 3,324,556, issued to Everett, discloses a pair of pendulums which are supported with respect to a platform. The pendulums are interconnected by a pair of arms which carry a writing instrument. The pendulums each carry a weight which may be adjusted longitudinally. The pendulums are pivoted so as to create a design with the writing instrument.
U.S. Pat. No. 3,494,037, issued to Arber, discloses a pair of pendulums supported with respect to a writing surface. A pair of arms are connected to the upper ends of the pendulums and to a writing instrument. A unique aspect of this disclosure is the weight, which may be filled with water in varying amounts, thereby changing the mass of the pendulum bob. A spring-type locking mechanism is used to support the pendulums with respect to the writing surface.
U.S. Pat. No. 3,977,085, issued to Sandifer, discloses a pendulum toy which may be used for drawing unique designs. This device has a secondary weighting system which counterbalances the weight placed on the pen. The pendulums also have a curved portion 46 which permits the pendulum to be mounted on a table surface without requiring a slot in the table surface.
U.S. Pat. No. 4,162,577, issued to Cosman, discloses a pendulum drawing machine including a pair of vertically oriented pendulum arms interconnected to a writing instrument, such as a pen, by a pair of arms 9 and 10. The arms include resilient portions at their interconnecting point with the pendulums. Also, a flexible connection is provided adjacent to the pen holder. This connection may be a flexible rectangular sheet material.
U.S. Pat. No. 4,199,867, issued to Cass, discloses a device for drawing unique designs in which the writing surface is supported by a plurality of flexible cords while the pen is held in a stationary position. Thus, the writing surface itself imitates the movement of a pendulum swinging back and forth so as to create unique designs.
Each of the disclosures discussed above are rather cumbersome and are capable of producing only a limited range of designs. Their motion also tends to dampen rather quickly and to transfer unwanted vibrations to the writing instrument. Also, the weights on the pendulums must be of a relatively large mass.
The present invention addresses the problems posed by prior art devices by creating a portable, lightweight device (typically constructed of plastic) that is self-contained, compact and easily assembled. A universal pen holder accepts most kinds of ball point pens and other writing instruments. The use of a control post at the junction of the members transferring the pendulum movement, and the use of ball and socket joints at the tip of the pendulum and end of the force transferring members, greatly improves peformance and control of the apparatus.